Methods for Manufacturing a Z-Directed Printed Circuit Board Component Having a Removable End Portion

ABSTRACT

A method for forming a Z-directed component for insertion into a mounting hole in a printed circuit board according to one example includes filling a first cavity having a tapered surface with a body material. A first layer of a constraining material is provided on top of the first cavity and has a second cavity having a width that is smaller than the first cavity. The second cavity is filled with the body material. Successive layers of the constraining material are provided on top of the first layer of the constraining material. Cavities of the successive layers of the constraining material are selectively filled with at least the body material to form layers of the main body portion of the Z-directed component. The constraining material is dissipated to release the Z-directed component from the constraining material and the Z-directed component is fired.

CROSS REFERENCES TO RELATED APPLICATIONS

This patent application is a divisional application of U.S. patentapplication Ser. No. 13/528,129, filed Jun. 20, 2012, entitled“Z-Directed Printed Circuit Board Components having a Removable EndPortion and Methods Therefor.” This patent application is related toU.S. patent application Ser. No. 13/528,097, filed Jun. 20, 2012,entitled “Process for Manufacturing a Z-Directed Component for a PrintedCircuit Board using a Sacrificial Constraining Material,” U.S. patentapplication Ser. No. 13/222,748, filed Aug. 31, 2011, entitled “DiePress Process for Manufacturing a Z-Directed Component for a PrintedCircuit Board,” U.S. patent application Ser. No. 13/222,418, filed Aug.31, 2011, entitled “Screening Process for Manufacturing a Z-DirectedComponent for a Printed Circuit Board,” U.S. patent application Ser. No.13/222,276, filed Aug. 31, 2011, entitled “Spin Coat Process forManufacturing a Z-Directed Component for a Printed Circuit Board,” U.S.patent application Ser. No. 13/250,812, filed Sep. 30, 2011, entitled“Extrusion Process for Manufacturing a Z-Directed Component for aPrinted Circuit Board” and U.S. patent application Ser. No. 13/284,084,filed Oct. 28, 2011, entitled “Continuous Extrusion Process forManufacturing a Z-Directed Component for a Printed Circuit Board,” whichare assigned to the assignee of the present application.

BACKGROUND

1. Field of the Disclosure

The present invention relates generally to processes for manufacturingprinted circuit board components and more particularly to a sacrificialconstraining process for manufacturing a Z-directed component for aprinted circuit board.

2. Description of the Related Art

The following United States patent applications, which are assigned tothe assignee of the present application, describe various “Z-directed”components that are intended to be embedded or inserted into a printedcircuit board (“PCB”): Ser. No. 12/508,131 entitled “Z-DirectedComponents for Printed Circuit Boards,” Ser. No. 12/508,145 entitled“Z-Directed Pass-Through Components for Printed Circuit Boards,” Ser.No. 12/508,158 entitled “Z-Directed Capacitor Components for PrintedCircuit Boards,” Ser. No. 12/508,188 entitled “Z-Directed Delay LineComponents for Printed Circuit Boards,” Ser. No. 12/508,199 entitled“Z-Directed Filter Components for Printed Circuit Boards,” Ser. No.12/508,204 entitled “Z-Directed Ferrite Bead Components for PrintedCircuit Boards,” Ser. No. 12/508,215 entitled “Z-Directed SwitchComponents for Printed Circuit Boards,” Ser. No. 12/508,236 entitled“Z-Directed Connector Components for Printed Circuit Boards,” and Ser.No. 12/508,248 entitled “Z-Directed Variable Value Components forPrinted Circuit Boards.”

As densities of components for printed circuit boards have increased andhigher frequencies of operation are used, some circuits' designs havebecome very difficult to achieve. The Z-directed components described inthe foregoing patent applications are designed to improve the componentdensities and frequencies of operation. The Z-directed components occupyless space on the surface of a PCB and for high frequency circuits, e.g.clock rates greater than 1 GHz, allow for higher frequency of operation.The foregoing patent applications describe various types of Z-directedcomponents including, but not limited to, capacitors, delay lines,transistors, switches, and connectors. A process that permits massproduction of these components on a commercial scale is desired.

SUMMARY

A Z-directed component for mounting in a mounting hole in a printedcircuit board according to one example embodiment includes a main bodyportion and a tapered end portion that facilitates insertion of theZ-directed component into the mounting hole in the printed circuitboard. The tapered end portion is removably attached to the main bodyportion such that the tapered end portion may be removed after theZ-directed component is inserted into the mounting hole in the printedcircuit board.

A method for installing a Z-directed component having a removabletapered lead-in into the mounting hole according to one exampleembodiment includes inserting the Z-directed component into the mountinghole in the printed circuit board with the removable tapered lead-inleading the insertion and after the Z-directed component is insertedinto the mounting hole, removing the removable lead-in from the rest ofthe Z-directed component.

A method for forming a Z-directed component for insertion into amounting hole in a printed circuit board according to one exampleembodiment includes filling a first cavity having a tapered surface witha body material to form a tapered end portion of the Z-directedcomponent. A first layer of a constraining material is provided on topof the first cavity. The first layer of the constraining material has asecond cavity having a width that is smaller than a width of the firstcavity. The second cavity is filled with the body material. Successivelayers of the constraining material are provided on top of the firstlayer of the constraining material. Each of the successive layers of theconstraining material has a cavity defining the outer shape of acorresponding layer of a main body portion of the Z-directed component.The cavities of the successive layers of the constraining material areselectively filled with at least the body material to form the layers ofthe main body portion of the Z-directed component. The constrainingmaterial is dissipated to release the Z-directed component from theconstraining material and the Z-directed component is fired.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of the variousembodiments, and the manner of attaining them, will become more apparentand will be better understood by reference to the accompanying drawings.

FIG. 1 is a perspective view of a Z-directed component according to oneexample embodiment.

FIG. 2 is a transparent perspective view of the Z-directed componentshown in FIG. 1 illustrating the internal arrangement of elements of theZ-directed component.

FIGS. 3A-3F are perspective views showing various example shapes for thebody of a Z-directed component.

FIGS. 4A-4C are perspective views showing various example side channelconfigurations for a Z-directed component.

FIGS. 5A-5H are perspective views showing various example channelconfigurations for the body of a Z-directed component.

FIG. 6A is a perspective view of a Z-directed component having O-ringsfor connecting to internal layers of a PCB and having a body havingregions comprised of similar and/or dissimilar materials according toone example embodiment.

FIG. 6B is a top plan view of the Z-directed component shown in FIG. 6A.

FIG. 6C is a schematic side elevation view of the Z-directed componentshown in FIG. 6A.

FIG. 7 is a schematic illustration of various example elements orelectronic components that may be provided within the body of aZ-directed component in series with a conductive channel.

FIG. 8 is a schematic cross-sectional view of a Z-directed componentflush mounted in a PCB showing conductive traces and connections to theZ-directed component according to one example embodiment.

FIG. 9 is a top plan view of the Z-directed component and PCB shown inFIG. 8.

FIG. 10 is a schematic cross-sectional view of a Z-directed componentflush mounted in a PCB showing ground loops for the Z-directed componentwith the Z-directed component further having a decoupling capacitorwithin its body according to one example embodiment.

FIG. 11 is a schematic cross-sectional view of a Z-directed componentflush mounted in a PCB showing a Z-directed component for transferring asignal trace from one internal layer of a PCB to another internal layerof that PCB according to one example embodiment.

FIG. 12 is a perspective view of a Z-directed capacitor havingsemi-cylindrical sheets according to one example embodiment.

FIG. 13 is an exploded view of another embodiment of a Z-directedcapacitor having stacked discs according to one example embodiment.

FIG. 14A is a perspective view of a sheet of substrate material used toform a Z-directed component according to one example embodiment.

FIG. 14B is a perspective view of a sheet of substrate materialaccording to another example embodiment having a rounded depressiontherein.

FIG. 14C is a perspective view of a sheet of substrate materialaccording to another example embodiment having a chamfered depressiontherein.

FIG. 15A is a perspective view of a Z-directed component having a domeformed on an end thereof according to one example embodiment.

FIG. 15B is a perspective view of a Z-directed component having achamfered end according to one example embodiment.

FIGS. 16-23 are sequential views showing the formation of a Z-directedcomponent according to one example embodiment.

FIG. 16 is a perspective view of an example screen for applyingconductive material to the substrate material.

FIG. 17 is a perspective view of the substrate material havingconductive applied thereon through the example screen shown in FIG. 16.

FIG. 18 is a perspective view showing a first layer of sacrificialconstraining material applied to the substrate material according to oneexample embodiment.

FIG. 19 is a perspective view showing a cavity in the first layer ofsacrificial constraining material filled with photoresist materialaccording to one example embodiment.

FIG. 20 is a perspective view showing the photoresist material removedafter the application of conductive material according to one exampleembodiment.

FIG. 21 is a perspective view showing body material applied to the firstlayer of sacrificial constraining material according to one exampleembodiment.

FIG. 22 is a perspective view showing additional conductive materialapplied to form a conductive plate for a Z-directed capacitor accordingto one example embodiment.

FIG. 23 is a perspective view showing a second layer of sacrificialconstraining material applied to form a second layer of the componentaccording to one example embodiment.

FIGS. 24-27 are sequential views showing the formation of a layer of aZ-directed component according to another example embodiment.

FIG. 24 is a perspective view showing conductive material applied to thesubstrate material according to one example embodiment.

FIG. 25 is a perspective view showing a first layer of the Z-directedcomponent formed in the sacrificial constraining material according toone example embodiment.

FIG. 26 is a perspective view showing two sets of vertical conductiveplates formed according to one example embodiment.

FIG. 27 is a perspective view showing the body material appliedaccording to one example embodiment.

FIG. 28 is a schematic view of an example array for constructingmultiple Z-directed components at one time.

FIG. 29 is a side cutaway view showing radial supports that extendbetween adjacent components across multiple component layers accordingto one example embodiment.

FIG. 30 is a perspective view showing the formation of a layer of aZ-directed component having multiple dielectric materials according toone example embodiment.

FIG. 31 is a perspective view showing a sheet of substrate materialhaving a depression for forming an indentation in the top or bottomsurface of the Z-directed component to facilitate removal of a roundedlead-in according to one example embodiment.

FIG. 32 is a perspective view showing a release layer applied to thesubstrate material and having a depression for forming an indentation inthe top or bottom surface of the Z-directed component according to oneexample embodiment.

FIG. 33 is a perspective view showing body material applied to thedepression shown in FIG. 31 according to one example embodiment.

FIG. 34 is a perspective view showing a layer of sacrificialconstraining material applied to the substrate material and havingcavities therein for connecting the removable lead-in to the componentaccording to one example embodiment.

FIG. 35 is a perspective view showing an additional layer of sacrificialconstraining material applied to form a layer of the Z-directedcomponent according to one example embodiment.

FIG. 36 is a perspective view showing body material applied to thesacrificial constraining material shown in FIG. 35.

FIG. 37 is a perspective view of a Z-directed component having aremovable rounded lead-in according to one example embodiment.

DETAILED DESCRIPTION

The following description and drawings illustrate embodimentssufficiently to enable those skilled in the art to practice the presentinvention. It is to be understood that the disclosure is not limited tothe details of construction and the arrangement of components set forthin the following description or illustrated in the drawings. Theinvention is capable of other embodiments and of being practiced or ofbeing carried out in various ways. For example, other embodiments mayincorporate structural, chronological, electrical, process, and otherchanges. Examples merely typify possible variations. Individualcomponents and functions are optional unless explicitly required, andthe sequence of operations may vary. Portions and features of someembodiments may be included in or substituted for those of others. Thescope of the application encompasses the appended claims and allavailable equivalents. The following description is, therefore, not tobe taken in a limited sense and the scope of the present invention isdefined by the appended claims.

Also, it is to be understood that the phraseology and terminology usedherein is for the purpose of description and should not be regarded aslimiting. The use of “including,” “comprising,” or “having” andvariations thereof herein is meant to encompass the items listedthereafter and equivalents thereof as well as additional items. Unlesslimited otherwise, the terms “connected,” “coupled,” and “mounted,” andvariations thereof herein are used broadly and encompass direct andindirect connections, couplings, and mountings. In addition, the terms“connected” and “coupled” and variations thereof are not restricted tophysical or mechanical connections or couplings.

Overview of Z-Directed Components

An X-Y-Z frame of reference is used herein. The X and Y axes describethe plane defined by the face of a printed circuit board. The Z-axisdescribes a direction perpendicular to the plane of the circuit board.The top surface of the PCB has a zero Z-value. A component with anegative Z-direction value indicates that the component is inserted intothe top surface of the PCB. Such a component may be above (extend past),flush with, or recessed below either the top surface and/or the bottomsurface of the PCB. A component having both a positive and negativeZ-direction value indicates that the component is partially insertedinto the surface of the PCB. The Z-directed components are intended tobe inserted into a hole or recess in a printed circuit board. Dependingon the shape and length of the component(s), more than one Z-directedcomponent may be inserted into a single mounting hole in the PCB, suchas being stacked together or positioned side by side. The hole may be athrough hole (a hole from the top surface through to the bottomsurface), a blind hole (an opening or recess through either the top orbottom surface into an interior portion or internal layer of the PCB) oran internal cavity such that the Z-directed component is embedded withinthe PCB.

For a PCB having conductive traces on both external layers, one externallayer is termed the top surface and the other the bottom surface. Whereonly one external layer has conductive traces, that external surface isreferred to as the top surface. The Z-directed component is referred toas having a top surface, a bottom surface and a side surface. Thereferences to top and bottom surfaces of the Z-directed componentconform to the convention used to refer to the top and bottom surfacesof the PCB. The side surface of a Z-directed component extends betweenthe top and bottom surfaces of the PCB and would be adjacent to the wallof the mounting hole in the PCB where the mounting hole is perpendicularto the face of the PCB. This use of top, bottom and side should not betaken as limiting how a Z-directed component may be mounted into a PCB.Although the components are described herein as being mounted in aZ-direction, this does not mean that such components are limited tobeing inserted into a PCB only along the Z-axis. Z-directed componentsmay be mounted normal to the plane of the PCB from the top or bottomsurfaces or both surfaces, mounted at an angle thereto or, depending onthe thickness of the PCB and the dimensions of the Z-directed component,inserted into the edge of the PCB between the top and bottom surfaces ofthe PCB. Further, the Z-directed components may be inserted into theedge of the PCB even if the Z-directed component is wider than the PCBis tall as long as the Z-directed component is held in place.

The Z-directed components may be made from various combinations ofmaterials commonly used in electronic components. The signal connectionpaths are made from conductors, which are materials that have highconductivity. Unless otherwise stated, reference to conductivity hereinrefers to electrical conductivity. Conducting materials include, but arenot limited to, copper, gold, aluminum, silver, tin, lead and manyothers. The Z-directed components may have areas that need to beinsulated from other areas by using insulator materials that have lowconductivity like plastic, glass, FR4 (epoxy & fiberglass), air, mica,ceramic and others. Capacitors are typically made of two conductingplates separated by an insulator material that has a high permittivity(dielectric constant). Permittivity is a parameter that shows theability to store electric fields in the materials like ceramic, mica,tantalum and others. A Z-directed component that is constructed as aresistor requires materials that have properties that are between aconductor and insulator having a finite amount of resistivity, which isthe reciprocal of conductivity. Materials like carbon, dopedsemiconductor, nichrome, tin-oxide and others are used for theirresistive properties. Inductors are typically made of coils of wires orconductors wrapped around a material with high permeability.Permeability is a parameter that shows the ability to store magneticfields in the material which may include iron and alloys likenickel-zinc, manganese-zinc, nickel-iron and others. Transistors such asfield effect transistors (“FETs”) are electronic devices that are madefrom semiconductors that behave in a nonlinear fashion and are made fromsilicon, germanium, gallium arsenide and others.

Throughout the application there are references that discuss differentmaterials, properties of materials or terminology interchangeably ascurrently used in the art of material science and electrical componentdesign. Because of the flexibility in how a Z-directed component may beemployed and the number of materials that may be used, it is alsocontemplated that Z-directed components may be constructed of materialsthat have not been discovered or created to date. The body of aZ-directed component will in general be comprised of an insulatormaterial unless otherwise called out in the description for a particulardesign of a Z-directed component. This material may possess a desiredpermittivity, e.g., the body of a capacitor will typically be comprisedof an insulator material having a relatively high dielectric constant.

PCBs using a Z-directed component may be constructed to have a singleconductive layer or multiple conductive layers as is known. The PCB mayhave conductive traces on the top surface only, on the bottom surfaceonly, or on both the top and bottom surfaces. In addition, one or moreintermediate internal conductive trace layers may also be present in thePCB.

Connections between a Z-directed component and the traces in or on a PCBmay be accomplished by soldering techniques, screening techniques,extruding techniques or plating techniques known in the art. Dependingon the application, solder pastes and conductive adhesives may be used.In some configurations, compressive conductive members may be used tointerconnect a Z-directed component to conductive traces found on thePCB.

The most general form of a Z-directed component comprises a body havinga top surface, a bottom surface and a side surface, a cross-sectionalshape that is insertable into a mounting hole of a given depth D withina PCB with a portion of the body comprising an insulator material. Allof the embodiments described herein for Z-directed components are basedon this general form.

FIGS. 1 and 2 show an embodiment of a Z-directed component. In thisembodiment, Z-directed component 10 includes a generally cylindricalbody 12 having a top surface 12 t, a bottom surface 12 b, a side surface12 s, and a length L generally corresponding to the depth D of themounting hole. The length L can be less than, equal to or greater thanthe depth D. In the former two cases, Z-directed component 10 would inone case be below at least one of the top and bottom surfaces of the PCBand in the other it may be flush with the two surfaces of the PCB. Wherelength L is greater than depth D, Z-directed component 10 would not beflush mounted with at least one of the top and bottom surfaces of thePCB. However, with this non-flush mount, Z-directed component 10 wouldbe capable of being used to interconnect to another component or anotherPCB that is positioned nearby. The mounting hole is typically athrough-hole extending between the top and bottom surfaces of the PCBbut it may also be a blind hole. When recessed below the surface of thePCB, additional resist areas may be required in the hole of the PCB tokeep from plating the entire circumferential area around the hole.

Z-directed component 10 in one form may have at least one conductivechannel 14 extending through the length of body 12. At the top andbottom ends 14 t and 14 b of conductive channel 14, top and bottomconductive traces 16 t, 16 b are provided on the top and bottom endsurfaces 12 t, 12 b of body 12 and extend from respective ends of theconductive channel 14 to the edge of Z-directed component 10. In thisembodiment, body 12 comprises an insulator material. Depending on itsfunction, body 12 of Z-directed component 10 may be made of variety ofmaterials having different properties. These properties include beingconductive, resistive, magnetic, dielectric, or semi-conductive orvarious combinations of properties as described herein. Examples ofmaterials that have the properties are copper, carbon, iron, ceramic orsilicon, respectively. Body 12 of Z-directed component 10 may alsocomprise a number of different networks needed to operate a circuit thatwill be discussed later.

One or more longitudinally extending channels or wells may be providedon the side surface of body 12 of Z-directed component 10. The channelmay extend from one of the top surface and the bottom surface of body 12toward the opposite surface. As illustrated, two concave side wells orchannels 18 and 20 are provided in the outer surface of Z-directedcomponent 10 extending the length of body 12. When plated or soldered,these channels allow electrical connections to be made to Z-directedcomponent 10, through the PCB, as well as to internal conductive layerswithin the PCB. The length of side channels 18 or 20 may extend lessthan the entire length of body 12.

FIG. 2 shows the same component as in FIG. 1 but with all the surfacestransparent. Conductive channel 14 is shown as a cylinder extendingthrough the center of Z-directed component 10. Other shapes may also beused for conductive channel 14. Traces 16 t and 16 b can be seenextending from ends 14 t and 14 b of conductive channel 14,respectively, to the edge of body 12. While traces 16 t and 16 b areshown as being in alignment with one another (zero degrees apart), thisis not a requirement and they may be positioned as needed for aparticular design. For example, traces 16 t and 16 b may be 180 degreesapart or 90 degrees apart or any other increment.

The shape of the body of the Z-directed component may be any shape thatcan fit into a mounting hole in a PCB. FIGS. 3A-3F illustrate possiblebody shapes for a Z-directed component. FIG. 3A shows a triangularcross-sectional body 40; FIG. 3B shows a rectangular cross-sectionalbody 42; FIG. 3C shows a frusto-conical body 44; FIG. 3D shows an ovatecross-sectional cylindrical body 46; and FIG. 3E shows a cylindricalbody 48. FIG. 3F shows a stepped cylindrical body 50 where one portion52 has a larger diameter than another portion 54. With this arrangement,the Z-directed component may be mounted on the surface of the PCB whilehaving a section inserted into a mounting hole provided in the PCB. Theedges of the Z-directed component may be beveled to help with aligningthe Z-directed component for insertion into a mounting hole in a PCB.Other shapes and combinations of those illustrated may also be used fora Z-directed component as desired.

For a Z-directed component, the channels for plating can be of variouscross-sectional shapes and lengths. The only requirement is that platingor solder material make the proper connections to the Z-directedcomponent and corresponding conductive traces in or on the PCB. Sidechannels 18 or 20 may have, for example, V-, C- or U-shapedcross-sections, semi-circular or elliptical cross-sections. Where morethan one channel is provided, each channel may have the same or adifferent cross-sectional shape. FIGS. 4A-4C illustrate three sidechannel shapes. In FIG. 4A, V-shaped side channels 60 are shown. In FIG.4B, U- or C-shaped side channels 62 are shown. In FIG. 4C, wavy orirregular cross-sectional side channel shapes 65 are shown.

The numbers of layers in a PCB varies from being single sided to beingover 22 layers and may have different overall thicknesses that rangefrom less than 0.051 inch to over 0.093 inch or more. Where a flushmount is desired, the length of the Z-directed component will depend onthe thickness of the PCB into which it is intended to be inserted. TheZ-directed component's length may also vary depending on the intendedfunction and tolerance of a process. The preferred lengths will be wherethe Z-directed component is either flush with the surfaces or extendsslightly beyond the surface of the PCB. This would keep the platingsolution from plating completely around the interior of the PCB holethat may cause a short in some cases. It is possible to add a resistmaterial around the interior of a PCB hole to only allow plating in thedesired areas. However, there are some cases where it is desired tocompletely plate around the interior of a PCB hole above and below theZ-directed component. For example, if the top layer of the PCB is aV_(CC) plane and the bottom layer is a GND plane then a decouplingcapacitor would have lower impedance if the connection used a greatervolume of copper to make the connection.

There are a number of features that can be added to a Z-directedcomponent to create different mechanical and electrical characteristics.The number of channels or conductors can be varied from zero to anynumber that can maintain enough strength to take the stresses ofinsertion, plating, manufacturing processes and operation of the PCB inits intended environment. The outer surface of a Z-directed componentmay have a coating that glues it in place. Flanges or radial projectionsmay also be used to prevent over or under insertion of a Z-directedcomponent into the mounting hole, particularly where the mounting holeis a through-hole. A surface coating material may also be used topromote or impede migration of the plating or solder material. Variouslocating or orienting features may be provided such as a recess orprojection, or a visual or magnetic indicator on an end surface of theZ-directed component. Further, a connecting feature such as a conductivepad, a spring loaded style pogo-pin or even a simple spring may beincluded to add an additional electrical connection (such as frameground) point to a PCB.

A Z-directed component may take on several roles depending on the numberof ports or terminals needed to make connections to the PCB. Somepossibilities are shown in FIGS. 5A-H. FIG. 5A is a Z-directed componentconfigured as 0-port device 70A used as a plug so that if a filter or acomponent is optional then the plug stops the hole from being plated.After the PCB has been manufactured, the 0-port device 70A may beremoved and another Z-directed component may be inserted, plated andconnected to the circuit. FIGS. 5B-5H illustrate various configurationsuseful for multi-terminal devices such as resistors, diodes,transistors, and/or clock circuits. FIG. 5B shows a 1-port or singlesignal Z-directed component 70B having a conductive channel 71 through acenter portion of the component connected to top and bottom conductivetraces 72 t, 72 b. FIG. 5C shows a 1-port 1-channel Z-directed component70C where one plated side well or channel 73 is provided in addition toconductive channel 71 through the component, which is connected to topand bottom conductive traces 72 t and 72 b. FIG. 5D shows a Z-directedcomponent 70D having two side wells 73 and 75 in addition to conductivechannel 71 through the component which is connected to top and bottomtraces 72 t, 72 b. The Z-directed component 70E of FIG. 5E has threeside wells 73, 75 and 76 in addition to conductive channel 71 throughthe component, which is connected to top and bottom traces 72 t, 72 b.FIG. 5F shows Z-directed component 70F having two conductive channels 71and 77 through the component each with their respective top and bottomtraces 72 t, 72 b and 78 t, 78 b and no side channels or wells.Z-directed component 70F is a two signal device to be primarily used fordifferential signaling. FIG. 5G shows a Z-directed component 70G havingone side well 73 and two conductive channels 71 and 77 each with theirrespective top and bottom traces 72 t, 72 b and 78 t, 78 b. FIG. 5Hshows Z-directed component 70H having one conductive channel 71 with topand bottom traces 72 t, 72 b and a blind well or partial well 78extending from the top surface along a portion of the side surface thatwill allow the plating material or solder to stop at a given depth. Forone skilled in the art, the number of wells and signals is only limitedby the space, required well or channel sizes.

FIGS. 6A-C illustrate another configuration for a Z-directed componentutilizing O-rings for use in a PCB having a top and bottom conductivelayer and at least one internal conductive layer. Z-directed component150 is shown having on its top surface 150 t, a locating feature 152 anda conductive top trace 154 t extending between a conductive channel 156and the edge of body 150 d on its top surface 150 t. A conductive bottomtrace (not shown) is provided on the bottom surface. Conductive channel156 extends through a portion of the body 150 d as previously described.Located on the side surface 150 s of body 150 d is a least onesemi-circular channel or grove. As shown, a pair of axially spaced apartcircumferential channels 158 a, 158 b is provided having O-rings 160 a,160 b, respectively disposed within channels 158 a, 158 b. A portion ofthe O-rings 160 a, 160 b extend out beyond the side surface 150 s of thebody 150 d. O-rings 160 a, 160 b would be positioned adjacent one ormore of the internal layers of the PCB to make electrical contract toone or more traces provided at that point in the mounting hole for theZ-directed component. Depending on the design employed, an O-ring wouldnot have to be provided adjacent every internal layer.

O-rings 160 a, 160 b may be conductive or non-conductive depending onthe design of the circuit in which they are used. O-rings 160 a, 160 bpreferably would be compressive helping to secure Z-directed component150 within the mounting hole. The region 162 of body 150 d intermediateO-rings 160 a, 160 b may be comprised of different material than theregions 164 and 166 of the body 150 d outside of the O-rings. Forexample, if the material of region 162 is of a resistive material andO-rings 160 a, 160 b are conductive then internal circuit board tracesin contact with the O-rings 160 a, 160 b see a resistive load.

Regions 164 and 166 may also be comprised of a material having differentproperties from each other and region 162. For example, region 164 maybe resistive, region 162 capacitive and region 166 inductive. Each ofthese regions can be electrically connected to the adjoining layers ofthe PCB. Further, conductive channel 156 and traces 154 t, 154 b do notneed to be provided. So for the illustrated construction, between thetop layer of the PCB and the first internal layer from the top, aresistive element may be present in region 164, a capacitive elementbetween the first internal layer and the second internal layer in region162 and an inductive element between the second internal layer and thebottom layer of the PCB in region 166. Accordingly, for a signaltransmitted from an internal trace contacting conductive O-ring 160 a toa second internal trace contacting conductive O-ring 160 b, the signalwould see an inductive load. The material for regions 162, 164, 166 mayhave properties selected from a group comprising conductive, resistive,magnetic, dielectric, capacitive or semi-conductive and combinationsthereof. The design may be extended to circuit boards having fewer ormore internal layers than that described without departing from thespirit of the invention.

In addition, regions 162, 164, 166 may have electronic components 167,169, 171 embedded therein and connected as described herein. Also, asillustrated for component 171, a component may be found within one ormore regions within the body of a Z-directed component. Internalconnections may be provided from embedded components to O-rings 160 a,160 b. Alternatively, internal connections may be provided from theembedded components to plateable pads provided on the side surface 150s.

The various embodiments and features discussed for a Z-directedcomponent are meant to be illustrative and not limiting. A Z-directedcomponent may be made of a bulk material that performs a networkfunction or may have other parts embedded into its body. A Z-directedcomponent may be a multi-terminal device and, therefore, may be used toperform a variety of functions including, but not limited to:transmission lines, delay lines, T filters, decoupling capacitors,inductors, common mode chokes, resistors, differential pair passthroughs, differential ferrite beads, diodes, or ESD protection devices(varistors). Combinations of these functions may be provided within onecomponent.

FIG. 7 illustrates various example configurations for a conductivechannel in a Z-directed component. As shown, channel 90 has a region 92intermediate the ends comprising a material having properties selectedfrom a group comprising conductive, resistive, magnetic, dielectric,capacitive or semi-conductive properties and combinations thereof. Thesematerials form a variety of components. Additionally, a component may beinserted or embedded into region 92 with portions of the conductivechannel extending from the terminals of the component. A capacitor 92 amay be provided in region 92. Similarly, a diode 92 b, a transistor 92 csuch as a MOSFET 92 d, a zener diode 92 e, an inductor 92 f, a surgesuppressor 92 g, a resistor 92 h, a diac 92 i, a varactor 92 j andcombinations of these items are further examples of materials that maybe provided in region 92 of conductive channel 90. While region 92 isshown as being centered within the conductive channel 90, it is notlimited to that location.

For a multi-terminal device such as transistor 92 c, MOSFET 92 d, anintegrated circuit 92 k, or a transformer 921, one portion of theconductive channel may be between the top surface trace and a firstterminal of the device and the other portion of the conductive channelbetween the bottom surface trace and a second terminal of the device.For additional device terminals, additional conductors may be providedin the body of the Z-directed component to allow electrical connectionto the remaining terminals or additional conductive traces may beprovided within the body of the Z-directed component between theadditional terminals and channels on the side surface of the body of aZ-directed component allowing electrical connection to an externalconductive trace. Various connection configurations to a multipleterminal device may be used in a Z-directed component.

Accordingly, those skilled in the art will appreciate that various typesof Z-directed components may be utilized including, but not limited to,capacitors, delay lines, transistors, switches, and connectors. Forexample, FIGS. 8 and 9 illustrate a Z-directed component termed a signalpass-through that is used for passing a signal trace from the topsurface of a PCB to the bottom surface.

Z-Directed Signal Pass-Through Component

FIG. 8 shows a sectional view taken along line 8-8 in FIG. 9 of a PCB200 having 4 conductive planes or layers comprising, from top to bottom,a ground (GND) plane or trace 202, a voltage supply plane V_(CC) 204, asecond ground GND plane 206 and a third ground GND plane or trace 208separated by nonconductive material such as a phenolic plastic such asFR4 which is widely used as is known in the art. PCB 200 may be used forhigh frequency signals. The top and bottom ground planes or traces 202and 208, respectively, on the top and bottom surfaces 212 and 214,respectively, of PCB 200 are connected to conductive traces leading upto Z-directed component 220. A mounting hole 216 having a depth D in anegative Z direction is provided in PCB 200 for the flush mounting ofZ-directed component 220. Here depth D corresponds to the thickness ofPCB 200; however, depth D may be less than the thickness of PCB 200creating a blind hole therein. Mounting hole 216, as illustrated, is athrough-hole that is round in cross-section to accommodate Z-directedcomponent 220 but may have cross sections to accommodate the insertionof Z-directed components having other body configurations. In otherwords, mounting holes are sized so that Z-directed components areinsertable therein. For example, a Z-directed component having acylindrical shape may be inserted into a square mounting hole and viceversa. In the cases where Z-directed component does not make a tightfit, resist materials will have to be added to the areas of thecomponent and PCB where copper plating is not desired.

Z-directed component 220 is illustrated as a three lead component thatis flush mounted with respect to both the top surface 212 and bottomsurface 214 of PCB 200. Z-directed component 220 is illustrated ashaving a generally cylindrical body 222 of a length L. A centerconductive channel or lead 224, illustrated as being cylindrical, isshown extending the length of body 222. Two concave side wells orchannels 226 and 228, which define the other two leads, are provided onthe side surface of Z-directed component 220 extending the length ofbody 222. Side channels 226 and 228 are plated for making electricalconnections to Z-directed component 220 from various layers of PCB 200.As shown, the ground plane traces on layers 202, 206, and 208 of PCB 100are electrically connected to side channels 226 and 228. V_(CC) plane204 does not connect to Z-directed component 220 as shown by the gap 219between V_(CC) plane 204 and wall 217 of mounting hole 216.

FIG. 9 illustrates a top view of Z-directed component 220 in PCB 200.Three conductive traces 250, 252 and 254 lead up to the edge of wall 217of mounting hole 216. As illustrated, trace 252 serves as ahigh-frequency signal trace to be passed from the top surface 212 to thebottom surface 214 of PCB 200 via Z-directed component 220. Conductivetraces 250 and 254 serve as ground nets. Center lead or conductivechannel 224 is electrically connected to trace 252 on the top surface212 of PCB 200 by a top trace 245 and plating bridge 230. Top trace 245on the top surface of Z-directed component 220 extends from the top end224 t of conductive channel 224 to the edge of Z-directed component 220.Although not shown, the bottom side of Z-directed component 220 andbottom surface 214 of PCB 200 is configured in a similar arrangement oftraces as shown on top surface 212 of PCB 200 illustrated in FIG. 9. Abottom trace on the bottom surface of Z-directed component 220 extendsfrom bottom of conductive channel 224 to the edge of Z-directedcomponent 220. A plating bridge is used to make the electricalconnection between the bottom trace and another high frequency signaltrace provided on the bottom surface of PCB 200. The transmission lineimpedance of the Z-directed component can be adjusted to match the PCBtrace impedance by controlling the conductor sizes and distances betweeneach conductor which improves the high speed performance of the PCB.

During the plating process, wells 256 and 258 formed between wall 217 ofmounting hole 216 and side channels 226 and 228 allow plating materialor solder pass from the top surface 212 to the bottom surface 214electrically interconnecting traces 250 and 254, respectively to sidechannels 226 and 228, respectively, of Z-directed component 220 and alsoto similarly situated traces provided on the bottom surface 214 of PCB200 interconnecting ground planes or traces 202, 206 and 208. Theplating is not shown for purposes of illustrating the structure. In thisembodiment, V_(CC) plane 204 does not connect to Z-directed component220.

One of the challenges for high frequency signal speeds is thereflections and discontinuities due to signal trace transmission lineimpedance changes. Many PCB layouts try to keep high frequency signalson one layer because of these discontinuities caused by the routing ofsignal traces through the PCB. Standard vias through a PCB have to bespaced some distance apart which creates high impedance between thesignal via and the return signal via or ground via. As illustrated inFIGS. 8 and 9, the Z-directed component and the return ground or signalshave a very close and controlled proximity that allow essentiallyconstant impedance from the top surface 212 to the bottom surface 214 ofPCB 200.

A Z-directed signal pass through component may also comprise adecoupling capacitor that will allow the reference plane of a signal toswitch from a ground plane, designated GND, to a voltage supply plane,designated V_(CC), without having a high frequency discontinuity. FIG.10 shows a cross-sectional view of a typical 4-layer PCB 300 with asignal trace 302 transferring between the top layer 304 and the bottomlayer 306. Z-directed component 310, similar to that shown in FIG. 5D,having body 312 connects signal trace 302 through center conductivechannel 314. Z-directed component 310 also comprises plated sidechannels 316 and 318 extending along the side surface 312 s of the body312. The top 314 t and bottom 314 b of conductive channel 314 areconnected to conductive traces 318 t and 318 b on the top 312 t andbottom 312 b of body 312. These, in turn, are connected to signal trace302 via top and bottom plating bridges 330 t and 330 b. Side channels316 and 318 are plated to GND plane 332 and V_(CC) plane 334,respectively. Connection points 336 and 338, respectively, illustratethis electrical connection. Schematically illustrated decouplingcapacitor 350 is internal to body 312 and is connected between sidechannels 316 and 318. Decoupling capacitor 350 may be a separatecapacitor integrated into the body 312 of Z-directed component 310 or itcan be formed by fabricating a portion of the body 312 of Z-directedcomponent 310 from the required materials with dielectric propertiesbetween conductive surfaces.

The path for signal trace 302 is illustrated with diagonal hatching andcan be seen to run from top layer 304 to bottom layer 306. GND plane 332and side channel 316 are electrically connected at 336 with the signalpath return indicated by the dark stippling 362. V_(CC) plane 334 andside channel 318 are electrically connected at 338 with the signal pathreturn indicated by the light stippling 364. As is known in the art,where a signal plane or trace is not to be connected to the insertedpart, those portions are spaced apart from the component as shown at370. Where a signal plane or trace is to be connected to an insertedcomponent, the signal plane or trace is provided at the wall or edge ofthe opening to allow the plating material or solder to bridgetherebetween as illustrated at points 330 t, 330 b, 336, and 338.

The vertically hatched portion 380 shows the high speed loop areabetween the signal trace and return current path described by the signaltrace 302 and the GND plane 332 or V_(CC) plane 334. The signal trace302 on the bottom surface 306 is referenced to power plane V_(CC) 334that is coupled to the GND plane 332 through decoupling capacitor 350.This coupling between the two planes will keep the high frequencyimpedance close to constant for the transition from one return plane toanother plane of a different DC voltage.

Internally mounting Z-directed components in a PCB greatly facilitatesthe PCB technique of using outer ground planes for EMI reduction. Withthis technique, signals are routed on the inner layers as much aspossible. FIG. 11 illustrates one embodiment of this technique. PCB 400is comprised of, from top to bottom, top ground layer 402, internalsignal layer 404, internal signal layer 406 and bottom ground layer 408.Ground layers 402 and 408 are on the top and bottom surfaces 400 t and400 b of PCB 400. A mounting hole 410, shown as a through-hole, extendsbetween the top and bottom surfaces 400 t and 400 b. Z-directedcomponent 420 is shown flush mounted in PCB 400. Z-directed component420 comprises body 422 having a center region 424 intermediate the top422 t and bottom 422 b of body 422 and two side channels 425 and 427 onside surface 422 s.

Side channels 425 and 427 and wall 411 of hole 410 form plating wells413 and 415 respectively. Center region 424 is positioned within body422 and extends a distance approximately equal to the distanceseparating the two internal signal layers 404 and 406. Side channel 425extends from the bottom surface 422 b of body 422 to internal signallevel 406 while side channel 427 extends from top surface 422 t of body422 to internal signal level 404. Here, side channels 425 and 427 extendonly along a portion of side surface 422 s of body 422. Conductivechannel 426 extends through center region 424 but does not extend to thetop and bottom surfaces 422 t, 422 b of body 422. FIG. 5H illustrates apartial channel similar to side channel 427. Conductive channel 426 hasconductive traces 428 t and 428 b extending from the top 426 t andbottom 426 b of conductive channel 426 to side channels 427 and 425,respectively. While illustrated as separate elements, conductive channel426 and traces 428 t, 428 b may be one integrated conductor electricallyinterconnecting side channels 425, 427. As shown, conductive trace 428 bis connected to internal signal layer 406 via plated side channel 425and well 413 while trace 428 t connects to internal signal level 404 viaside channel 427 and well 415. Ground layers 402 and 408 are notconnected to Z-directed component 420 and are spaced away from mountinghole 410 as previously described for FIGS. 8 and 10. As shown by doubleheaded dashed arrow 430, a signal on signal layer 406 can be via′d tosignal layer 404 (or vice versa) via Z-directed component 420 through apath extending from well 413, side channel 425, trace 428 b, conductivechannel 426, trace 428 t, side channel 427, and well 415 to allow thesignal to remain on the inner layers of PCB 400 with ground layers 402and 408 providing shielding.

Z-Directed Decoupling Capacitors

FIGS. 12 and 13 illustrate two additional example Z-directed componentsin the form of decoupling capacitors. In FIG. 12, a Z-directed capacitor500 is shown with a body 502 having a conductive channel 504 and twoside channels 506 and 508 extending along its length similar to thosepreviously described. Conductive channel 504 is shown connected to asignal 526. Vertically oriented interleaved partial cylindrical sheets510, 512 forming the plates of Z-directed capacitor 500 are connected toreference voltages such as voltage V_(CC) and ground (or any othersignals requiring capacitance) and are used with intervening layers ofdielectric material (not shown). Partial cylindrical sheet 510 isconnected to plated channel 506 which is connected to ground 520.Partial cylindrical sheet 512 is connected to plated channel 508 whichis connected to supply voltage V_(CC) 522. Sheets 510, 512 may be formedof copper, aluminum or other material with high conductivity. Thematerial between the partial cylindrical sheets is a material withdielectric properties. Only one partial cylindrical sheet is shownconnected to each of V_(CC) 522 and ground 520; however, additionalpartial cylindrical sheets may be provided to achieve the desiredcapacitance/voltage rating.

Another embodiment of a Z-directed capacitor is shown in FIG. 13 usingstacked support members connected to voltage V_(CC) or ground.Z-directed capacitor 600 is comprised of center conductive channel 601and a body 605 comprised of a top member 605 t, a bottom member 605 b,and a plurality of support members 610 (illustrated as disks) betweenthe top and bottom members 605 t, 605 b.

Center conductive channel 601 extends through openings 615 in theassembled Z-directed capacitor 600 and openings 602 t and 602 b, all ofwhich are sized to closely receive the center conductor. Centerconductive channel 601 is electrically connectable to conductive traces603 t and 603 b on the top and bottom portions 605 t, 605 b forming asignal path for signal 626. This connection is made by plating orsoldering. Center conductive channel 601 is connected to signal 626 viaconductive trace 603 t. The bottom end of conductive channel 601 isconnected in a similar fashion to a signal trace (not shown) viaconductive trace 603 b.

Opposed openings 607 t and 608 t are provided at the edge of top portion605 t. Bottom portion 605 b is of similar construction as top portion605 t having opposed openings 607 b and 608 b provided at the edge.Between top and bottom portions 605 t, 605 b are a plurality of supportmembers 610, which provide the capacitive feature. Support members 610each have at least one opening 613 at their outer edge and an inner hole615 allowing for passage of conductive channel 601 therethrough. Asshown, two opposed openings 613 are provided in each support member 610.When assembled, the opposed openings 607 t, 607 b, 608 t, 608 b, and 613align to form opposed side channels 604 and 608 extending along the sidesurface of Z-directed capacitor 600. Side channel 604 is shown connectedto reference voltage such as ground 620 and side channel 606 to anotherreference voltage such as V_(CC) 622. Support members 610 may befabricated from a dielectric material and may be all of the same orvarying thickness allowing for choice in designing the desiredproperties for Z-directed capacitor 600.

Annular plating 617 is provided on one of top and bottom surfaces ofsupport member 610 or, if desired, on both surfaces. Annular plating isshown on the top surface of each support member but location of theannular plating can vary from support member to support member. Annularplating 617 generally conforms to the shape of the support member andextends from one of the edge openings 613 toward the other if anadditional opening is provided. The annular plate 617 is of a diameteror dimension or overall size that is less than the diameter, dimensionor overall size of support member 610 on which it is affixed. While theplate 617 is described as annular, other shapes may also be usedprovided that the plating does not contact the center conductive channelor extend to the edge of the support member on which it is plated orotherwise affixed. The annular plate does contact one of the edgeopenings 613 but is spaced apart from the other openings if more thanone channel is present in the side surface of the body of Z-directedcapacitor 600. Also, there is an opening 619 in annular plate 617 havinga larger diameter than opening 615 in annular plate 617 through whichconductive channel 601 passes. Opening 619 has a larger diameter thanthat of conductive channel 601 leaving annular plate 617 spaced apartfrom conductive channel 601.

As illustrated, the support members 610 are substantially identicalexcept that when stacked, alternate members are rotated 180 degrees withrespect to the member above or below it. This may be referred to as a1-1 configuration. In this way, alternate members will be connected toone or the other of the two side channels. As shown in FIG. 13, theannular plating on the upper one of the two support members 610 isconnected to side channel 608 and voltage V_(CC) 622 while the annularplating on the lower one of the two support members 610 is connected toside channel 604 and ground 620. Other support member arrangements mayalso be used such as having two adjacent members connected to the samechannel with the next support member being connected to the oppositechannel which may be referred to as a 2-1 configuration. Otherconfigurations may include 2-2, 3-1 and are a matter of design choice.The desired capacitance or voltage rating determines the number ofsupport members that are inserted between top and bottom portions 605 t,605 b. Although not shown, dielectric members comprised of dielectricmaterial and similarly shaped to support members 610 may be interleavedwith support members 610. Based on design choice, only a single channelmay be used or more channels may be provided and/or the annular platingmay be brought into contact with the center conductive channel and notin contact with the side channels. Again, the embodiments for Z-directedcapacitors are for purposes of illustration and are not meant to belimiting.

With either design for a Z-directed capacitor, a second conductivechannel may be provided in parallel with the first conductive channelthat is disposed within the conductive plates to create a differentialdecoupling capacitor. Another embodiment of a Z-directed capacitor canbe constructed from FIG. 12 or FIG. 13 by connecting the centerconductive channel to one of the reference voltages at each supportmember that also has its annular plating connected to the same referencevoltage. This may be accomplished simply by connecting the conductivechannel to the annular plating as schematically illustrated by thejumper 621. In practice, the annular opening 619 in the annular plate617 would be sized so that the annular plate and conductive channel 601would be electrically connected. This component may be placed directlybelow a power pin or ball of an integrated circuit or other surfacemounted component for optimum decoupling placement.

Again, the Z-directed signal pass-through components illustrated inFIGS. 8-11 and the Z-directed decoupling capacitors illustrated in FIGS.12 and 13 provide merely a few example applications of a Z-directedcomponent. Those skilled in the art will appreciate that various othertypes of Z-directed components may be utilized including, but notlimited to, transmission lines, delay lines, T filters, decouplingcapacitors, inductors, common mode chokes, resistors, differential pairpass throughs, differential ferrite beads, diodes, or ESD protectiondevices (varistors).

Process for Manufacturing a Z-Directed Component Using a SacrificialConstraining Material

A process for manufacturing the Z-directed components on a commercialscale is provided. The process employs a sacrificial constrainingmaterial used as a structure to define and support the outer boundaryand thickness of each layer being formed to construct the Z-directedcomponent. The constraining layer allows the component to be constructedin an unfired state (e.g., a “green” state where the component body isformed from ceramic) and then be fired to solidify its form.

FIG. 14A shows a sheet 700 of substrate material that is used as a baseto assemble the Z-directed component on top of. The substrate materialis compatible with the firing of the Z-directed component such that thefiring temperature will not degrade the ability of sheet 700 to supportthe Z-directed component. The substrate material may be, for example,ceramic, glass or a silicon wafer. In the embodiment shown in FIG. 14A,sheet 700 includes a flat top surface 702. Alternatively, top surface702 may include a tapered depression or dimple such as a rounded dimple704 (shown in FIG. 14B) or a chamfered dimple 706 (shown in FIG. 14C).For simplicity, FIGS. 14B and 14C show a single dimple 704, 706,respectively; however, it will be appreciated that top surface 702 mayinclude an array of depressions or dimples in order to permit theconstruction of many components at one time to maximize manufacturingefficiency. The depressed or dimpled top surface 702 allows a Z-directedcomponent to be constructed that includes a chamfered, domed or otherform of tapered lead-in on at least one of the top and bottom end of theZ-directed component. Such a lead-in may be desired in order to easeinsertion of the Z-directed component into the mounting hole in the PCB.For example, FIG. 15A shows a Z-directed component 800 having a dome 802formed on an end thereof. FIG. 15B shows a Z-directed component 810having a chamfered end 812. The dome 802 or chamfer 812 may be part ofthe component or attached thereto. In one embodiment, the dome 802 orchamfer 812 is a separate part that is partially inserted into themounting hole in the PCB. In this embodiment, the Z-directed componentis then inserted behind the dome 802 or chamfer 812 to push it throughthe mounting hole causing the dome 802 or chamfer 812 to expand themounting hole and prevent the component from cutting or tearing the PCB.Where the dome 802 or chamfer 812 is attached to the Z-directedcomponent, it may be configured to remain attached to the Z-directedcomponent following insertion into the mounting hole in the PCB or itmay be used to facilitate insertion and then removed.

With reference back to FIGS. 14A-14C, top surface 702, including anydimples or depressions therein, is coated with a release layer 708 thatprevents the Z-directed component from adhering to the substratematerial thereby allowing the component to be separated from sheet 700without damaging or deforming the component. Release layer 708 may beapplied to top surface 702 of sheet 700 by any suitable method capableof applying a thin layer of substantially equal thickness to thesubstrate material. For example, release layer 708 may be sprayed,squeegeed, spun, or laminated onto sheet 700. Release layer 708 isformed from a polymer or other material that does not react with any ofthe chemicals or radiations used during the construction of theZ-directed component so that the structure of release layer 708 does notchange during the manufacturing process. In one embodiment, releaselayer 708 includes a polyimide (or a polyimide with glass fillers) dueto its strength and resistance to etching chemicals. Suitable polyimidesinclude, for example, UPILEX® available from Ube Industries, Ltd.,Tokyo, Japan and KAPTON® available from E.I. du Pont de Nemours andCompany (DuPont™), Wilmington, Del., USA. Release layer 708 is expectedto dissipate during the firing process allowing the Z-directed componentto release from sheet 700.

Each Z-directed component is then constructed one layer at a time on topsurface 702 having release layer 708. If the bottom surface of the firstlayer built on sheet 700 (which may be the top or bottom surface of thecomponent) requires surface conductors, the conductive material can beapplied to top surface 702 having release layer 708 coated thereon. Forexample, FIG. 16 shows an example screen 710 that may be used to applyconductive material to top surface 702. Screen 710 includes openings 712that allow conductive material to be applied to top surface 702 havingrelease layer 708 coated thereon. In the example embodiment shown inFIG. 16, screen 710 includes a first opening 712 a sized and shaped topermit the formation of a conductive trace from a center portion of thetop or bottom surface of the Z-directed component to an edge of thecomponent. In this embodiment, screen 710 also includes openings 712 band 712 c sized and shaped to permit the formation of a conductivesegment forming a portion of a conductive side channel in the component.Any suitable method may be used to apply the conductive materialincluding, for example, etching, depositing (such as physical vapordeposition (PVD) or plating), spin coating, screen printing or jetting.

FIG. 17 shows sheet 700 having conductive material 714 applied on topsurface 702. Conductive material 714 is illustrated with diagonalhatching. Specifically, conductive material 714 includes a conductivetrace 715 positioned to run from a center portion of the top or bottomsurface of the Z-directed component to an edge of the component forelectrically connecting an interior conductive channel through thecomponent to a trace on the PCB. Conductive material 714 also includesconductive segments 716 and 717 that form a portion of a conductive sidechannel in the component. Conductive material 714 may include binders tocause it to adhere to itself and to subsequent layers of the component.In this embodiment, the binders are allowed to cure between successivesteps of the manufacturing process so that subsequent steps do not causemigration of material. Alternatively, where PVD or plating is used toapply conductive material 714, conductive material 714 may be pure metalor metal alloy.

As shown in FIG. 18, a first layer of a sacrificial constrainingmaterial 720 is applied to top surface 702 having release layer 708coated thereon. Sacrificial constraining material 720 forms a cavity 722that defines the outer shape of the component. In the example embodimentillustrated, cavity 722 includes a generally cylindrical wall 724defining a generally cylindrical shape of the first layer. Wall 724includes a pair of protrusions 726, 728 that define a corresponding pairof side channels in the component. The thickness of this layer ofsacrificial constraining material 720 is the same as the desired heightof the first layer of the Z-directed component. In some embodiments, thelayers of the component have a height that is between about 0.039 miland about 62 mil (about 1 μm and about 1.57 mm), including allincrements and values therebetween, depending on the application inwhich the Z-directed component will be used. It will be appreciated thatthe layers may be made thinner than about 1 μm as the technologyadvances. The heights of the layers making up a Z-directed component maybe uniform or may vary within a single Z-directed component. In oneembodiment, sacrificial constraining material 720 is the same materialas release layer 708. Alternatively, sacrificial constraining material720 may be any suitable material that will survive the chemicals andradiations used during the construction of the Z-directed component. Anysuitable method may be used to apply sacrificial constraining material720 including, for example, etching, depositing (such as physical vapordeposition (PVD) or plating), spin coating, screen printing or jetting.

The layer of sacrificial constraining material 720 may also includevarious channels 730 therethrough that extend from cavity 722 outward.Channels 730 will be filled with the material forming the body of thecomponent (or another suitable material) in order to provide structuralsupport for the component during the firing process while sacrificialconstraining material 720 dissipates as discussed in greater detailbelow. FIG. 18 shows four channels 730 a, 730 b, 730 c, 730 d, althoughmore or fewer channels 730 may be used as desired depending on theamount of structural strength needed. For example, in one embodiment,six channels 730 are provided in sacrificial constraining material 720to maximize the structural strength. Channels 730 are preferably thin sothat the radial support structures formed in channels 730 can be easilybroken away to release the component after the component has been formedand fired. In the example embodiment illustrated, channels 730 areformed through wall portion 724 so as to connect with cavity 722. Inthis manner, the radial support structures formed by channels 730 areconnected to the body of the Z-directed component. Alternatively, a thinlayer of sacrificial constraining material 720 may be positioned betweenchannels 730 and cavity 722 to prevent surface irregularities on theside surface of the Z-directed component when the component is separatedfrom the radial support structures. Further, one or more of cavities 730may be omitted in order to indicate the orientation of the part (i.e.,by arranging cavities 730 asymmetrically), to reduce the amount ofwasted component body material and to simplify the separation of thecomponent(s) from the support structures.

Cavity 722 and channels 730 are then filled with photoresist material,which may be any photo imageable epoxy or similar material. Thephotoresist material is then selectively exposed to a radiation sourcethrough a mask to create voids where conductive material is desired inthe first layer of the component. Either positive or negativephotoresist may be used as desired. FIG. 19 shows cavity 722 andchannels 730 having photoresist material 732 (illustrated withx-hatching) therein after photoresist material 732 has been selectivelyetched to form voids 734 where conductive material is desired accordingto one example embodiment. Specifically, voids 734 include a center void734 a for forming a signal path through an interior portion of thecomponent along the component's length. A pair of voids 734 b, 734 c areformed at opposite edges of cavity 722 next to protrusions 726, 728 forforming a pair of conductive side channels in the component. Anadditional void 734 d is formed where conductive trace 715 meets theedge of cavity 722 for forming a conductive segment on the side surfaceof the component along its length to establish a connection toconductive trace 715.

Voids 734 are then filled with conductive material 714. Voids 734 may befilled, for example, by squeegeeing, depositing, spin coating, screenprinting or jetting as discussed above. After the conductive materialbinders have cured, the remaining photoresist material 732 is removed asshown in FIG. 20. As discussed above, sacrificial constraining material720 is selected to survive the etching process. In the exampleembodiment illustrated, a center conductive channel 736 has been formedfrom void 734 a that extends along the height of the layer of thecomponent and electrically connects to trace 715. Additional conductivematerial 714 has been added to conductive segments 716 and 717 throughvoids 734 b, 734 c, respectively. An additional conductive segment 739has been formed from void 734 d that extends along the height of thelayer and electrically connects to trace 715 at the edge of cavity 722.In some instances, manufacturing variations in the thickness of the PCBand the length of the Z-directed component may prevent the Z-directedcomponent from being perfectly flush with both the top and bottomsurfaces of the PCB. Conductive segment 739 forms a bridge between trace715 and a corresponding trace on the PCB when the top or bottom surfaceof the Z-directed component extends past the corresponding top or bottomsurface of the PCB. As a result, conductive segment 739 permits trace715 on the Z-directed component to connect to the trace on the PCB evenif the top or bottom surface of Z-directed component is not flush withthe corresponding top or bottom surface of the PCB.

The remainder of cavity 722 is then filled with the material 740 formingthe body 742 of the component as shown in FIG. 21. Body material 740 isillustrated with a dotted fill. At this stage, a first layer of theZ-directed component is formed. Body material 740 may include a singledielectric material that has a relative permittivity from about 3, e.g.,polymers, to over 10,000, e.g., barium titanate (BaTiO₃). For example, amaterial with a relatively high dielectric value may be used in aZ-directed decoupling capacitor and a material with a relatively lowdielectric value may be used in a Z-directed signal pass-throughcomponent. If a Z-directed component is desired to have an inductivefunction or a delay line then a ferrite material may be selected thathas a low or high relative permeability with a range of about 1 to about50,000. If a Z-directed component is desired to have some degree ofconductivity then a conductive material may be mixed with a dielectricmaterial to create a desired resistance.

Channels 730 are also filled with body material 740 to form radialsupports 744. Body material 740 may include a binder material asnecessary. Cavity 722 and channels 730 are filled so that body material740 is flush with the top surface of sacrificial constraining material720. As discussed above, this may be done, for example, by squeegeeing,depositing, spin coating, screen printing or jetting. Further, asdiscussed above, many different materials are contemplated for the bodyof the component, such as an insulator material, which may be adielectric material. Conductive channel 736, conductive segments 716,717 and 739 are shown exposed through the top surface of the layer ofbody 742. It will be appreciated that instead of first selectivelyapplying conductive material 714 in cavity 722 and then applying bodymaterial 740, this sequence may be reversed as desired to insteadselectively apply body material 740 prior to applying conductivematerial 714.

Once the binder material in body material 740 cures, additional layersmay be formed on top of the first layer according to the same sequence.That is, additional layers of sacrificial constraining material 720 areapplied one at a time each forming a cavity that defines the shape ofthe next layer. Conductive material 714, body material 740 and/or anyother desired material(s) are selectively applied as desired to form thenext component layer. This process is repeated until the entirecomponent is formed. For example, FIG. 22 shows additional conductivematerial 714 applied on top of center conductive channel 736 andconductive segments 716, 717 of the conductive side channels. Conductivesegment 739 does not need to be extended further as this element isprovided to ensure that a connection can be made between conductivetrace 715 and a corresponding trace on the top or bottom surface of thePCB. Further, additional conductive material 714 has been applied toform a conductive plate 746 on a top surface of the first layer in orderto form a Z-directed capacitor having horizontal plates as discussedabove with respect to FIG. 13. Conductive plate 746 is connected toconductive segment 717 but not conductive segment 716. As each layer ofthe capacitor is built, this sequence is reversed such that theconnection to each conductive plate alternates between conductivesegment 716 and conductive segment 717. The conductive plates mayalternate in any pattern desired such as 1-1, 2-1, 3-1, 3-2, etc.

As shown in FIG. 23, additional sacrificial constraining material 720may then be applied on top of the first layer of sacrificialconstraining material 720 to define a cavity 748 for forming a secondlayer of the Z-directed component. The second layer of sacrificialconstraining material 720 may or may not include channels 730 extendingfrom cavity 748 depending on whether additional structural support isneeded. If additional channels are included, they may be provided in thesame number and locations as the first layer or in a different numberand/or at different locations. Preferably, as few channels 730 aspossible are used in order to minimize the occurrence of defects on theside surface of the component when the component is separated fromradial supports 744. After each layer of the Z-directed component hasbeen formed, conductive material 714 may applied to the top surface ofthe top layer as desired. A thin layer of body material 740 may also beapplied to the top surface of the top layer so that body material 740 isflush with conductive material 714 to match the geometry of the bottomsurface of the bottom layer.

The configuration of conductive material 714 shown in FIGS. 20-23 ismeant to provide an example of the formation of a layer of theZ-directed component and it will be appreciated that any suitableamount, shape, size and placement of conductive material 714 may be useddepending on the component desired. Specifically, while FIGS. 18-20illustrate the formation of two conductive side channels, any number ofconductive side channels may be formed as desired including noconductive side channels. Similarly, although one interior conductivechannel 736 is shown, any number of conductive channels through aninterior portion of the component may be formed as desired. Further,although generally cylindrical cavities 722, 748 are shown, manydifferent component body shapes may be used as discussed above.

Although the formation of a Z-directed capacitor having horizontalplates is illustrated in FIGS. 22 and 23, a Z-directed capacitor mayalso be formed having vertical plates similar to the component shown inFIG. 12. To form a vertical plate capacitor, conductive material 714 mayfirst be screened onto top surface 702 of sheet 700 having release layer708 coated thereon to form a pair of conductive segments 750, 751 asshown in FIG. 24. Each conductive segment 750, 751 forms a portion of arespective conductive side channel in the component. A first layer ofsacrificial constraining material 720 is then added and a cavity thereinis filled with body material 740 as shown in FIG. 25. Conductivesegments 750, 751 extend through the layer of body material 740. Anotherlayer of sacrificial constraining material 720 is then added forminganother cavity 755. Conductive material 714 is applied in cavity 755 inan alternating pattern as shown in FIG. 26 to form segments of two sets752, 753 of vertical conductive plates. Set 752 is illustrated withheavy diagonal hatching while set 753 is illustrated with light diagonalhatching. In the example embodiment shown, sets 752, 753 of conductivesegments forming vertical conductive plates are positioned in a 1-1pattern; however, the plates may be arranged in any pattern desired. Set752 of conductive plate segments is connected to conductive segment 750forming a first conductive side channel in the component but spaced fromconductive segment 751. Similarly, set 753 of conductive plate segmentsis connected to conductive segment 751 but not conductive segment 750.

As shown in FIG. 27, cavity 755 may then be filled with body material740 to complete the layer of the component. Body material 740 is flushwith the tops of conductive segments 750, 751 and sets 752, 753 of theconductive segments forming the vertical plates. The rest of thecomponent is then built layer by layer on top of the first formed layeras discussed above. Conductive segments 750, 751 extend along the lengthof the component and form conductive side channels in the component.Similarly, sets 752, 753 of conductive segments extend along the lengthof the component and form the vertical conductive plates of thecapacitor. While the vertical plates in the example embodimentillustrated are relatively straight, as shown in FIG. 12, curved platesmay also be used as desired. Further, although FIGS. 22 through 27illustrate the formation of two different types of Z-directedcapacitors, many different types of components are contemplated asdiscussed above including, but not limited to, transmission lines, delaylines, T filters, decoupling capacitors, inductors, common mode chokes,resistors, differential pair pass throughs, differential ferrite beads,diodes, and ESD protection devices (varistors).

FIG. 28 shows an example array 770 for constructing multiple Z-directedcomponents 772 at one time. Array 770 positions the components 772 asclose together as possible to maximize manufacturing efficiency. Radialsupports 744 are shown linking pairs of components 772 together. In theexample embodiment shown, concave triangles 774 formed from eithersacrificial constraining material 720 or body material 740 are leftbetween the components 772. These triangles 774 will be waste materialwhen the manufacturing process is complete.

Radial supports 744 may extend between components 772 along one layer asillustrated in FIGS. 21 and 22. Alternatively, some or all of radialsupports 744 may extend across multiple layers. For example, FIG. 29shows a side cutaway view of array 770 having layers 771 a, 771 b, 771c, 771 d. Body material 740 is illustrated with a dotted fill andsacrificial constraining material 720 is illustrated without a fill. Inthis example, radial support 744 ascends in a stepped manner from nearthe bottom of one component 772 a to near the top of an adjacentcomponent 772 b in array 770. Each segment of radial support 744overlaps with the segment on the previous layer. An array 770 thatincorporates both radial supports 744 that extend across a single layerand radial supports 744 that extend across multiple layers may be usedto provide increased mechanical stability.

After the Z-directed component has been formed, a firing process isapplied to solidify the part. The firing process also shrinks the partto its final dimensions. Accordingly, the component is formed largerthan the final desired size to account for this shrinkage. As thecomponent is fired, sacrificial constraining material 720 dissipatesleaving radial supports 744 to hold the component in place.Alternatively, sacrificial constraining material 720 may be dissolvedusing a solvent or a plasma treatment before or after firing. Where thefiring process is performed after dissolving sacrificial constrainingmaterial 720, the component may be prebaked prior to performing thesolvent or plasma treatment in order to stabilize the component duringthe treatment and firing. The components can then be easily removed fromradial supports 744 using a punching method to break the components awayfrom radial supports 744. For example, array 770 of components can bepositioned above and then punched into an array of cavities in apackaging plate that can assist with singling the components. Eachcavity can help align the component as it is punched out of radialsupports 744. The punched components can then be packaged using anautomated device that pushes the part out of the packaging plate into atape and reel system or a similar packaging system. To facilitatesingulation, radial supports 744 connecting adjacent components may beattached part way up the side walls of the components (spaced from thetop or bottom surface of the components) to permit more of eachcomponent to be constrained in its corresponding cavity duringseparation from radial supports 744.

Using a sacrificial constraining material that dissipates during firingto support the component as it is built eliminates the need to eject thecomponent from a fixed constraining structure prior to firing whichcould result in smearing, tearing or otherwise damaging the structure ofthe component. The constraining material in combination with radialsupports 744 prevents the components from moving during the firingprocess which could deform the parts or cause them to touch and sticktogether. Further, the process described herein is compatible with thickor thin film processes.

The Z-directed components can be tested for yield and performance whilethey are still connected to radial supports 744 or after they areseparated. Conductive material 714 exposed on an outer surface of thecomponents may be over-plated using electrolysis techniques to provide adifferent surface conductive material from the conductive material 714present in the interior of the component. Electrolysis techniques mayalso be used as each layer is formed to alter the surfacecharacteristics of conductive material 714 if desired. Further, exteriorportions of conductive material 714 may be applied after the componenthas been formed instead of as each layer is formed. For example,conductive material 714 may be applied to the side channels in thecomponent after the component is formed. Resist areas may be added tothe Z-directed components to keep the conductive material from stickingto areas that are not intended to be conductive. Glue areas may beapplied to the components to assist with retaining them in a PCB.Visible markings and/or locating features may also be added to theZ-directed components to assist with assembly into a PCB.

Once production of a Z-directed component is complete, it is ready to beinserted into the mounting hole of the PCB. As discussed above, thecomponent may be mounted normal to the plane of the PCB from the top orbottom surfaces or both surfaces, mounted at an angle thereto orinserted into the edge of the PCB between the top and bottom surfaces ofthe PCB. In some embodiments, the Z-directed component is press fit intothe mounting hole. This press fit may be in the form of an interferencefit between the component and the mounting hole. After the Z-directedcomponent is positioned in the mounting hole, a conductive platingbridge may be applied to connect one or more traces on the top and/orbottom surface of the component to a corresponding trace on the PCB.Further, where the Z-directed component includes side channels therein,additional conductive plating may be applied to these side channels toform the desired signal connections between the Z-directed component andthe PCB.

While FIGS. 18-23 illustrate the use of a single body material 740 toform the Z-directed component, it will be appreciated that multiple bodymaterials may be used as desired such as, for example, multipledielectric materials each having a different dielectric constant. Forexample, FIG. 30 shows a first layer of a Z-directed capacitor formedfrom a first body material 740 a having a relatively low dielectricconstant (e.g., between about 6 and about 100) surrounding conductivechannel 736 and a second body material 740 b having a relatively highdielectric constant (e.g., between about 2,000 and about 25,000)surrounding the first body material 740 a. Body material 740 a isillustrated with a light dotted fill and body material 740 b isillustrated with a heavy dotted fill. Each body material 740 a, 740 bmay be selectively applied using the process discussed above.

In some embodiments, the tapered end of the component formed using thedepressions or dimples discussed above with respect to FIGS. 14B and 14Cmay be removable. In these embodiments, the tapered end may serve as alead-in to ease insertion of the Z-directed component into the mountinghole in the PCB and then be removed after the component is mounted inthe PCB. The top or bottom surface of the component may include aprojection or indentation to facilitate removal of the tapered endportion of the component. For example, FIG. 31 illustrates an examplesheet 700 of substrate material for forming an indentation in the top orbottom surface of the component to facilitate removal of a roundedlead-in. In the example embodiment illustrated, a portion of roundeddimple 704 formed in top surface 702 of sheet 700 includes a protrusion776 that forms a corresponding indentation in the bottom surface of thebottom layer of the component (which again may be the top or bottomsurface of the component in use in the PCB). Top surface 702 includingrounded dimple 704 and protrusion 776 are coated with release layer 708as discussed above. The indentation in the top or bottom surface of thecomponent allows the lead-in to be twisted and separated from thecomponent as discussed in greater detail below.

In another embodiment, a tapered end portion may be formed on thecomponent using sheet 700 shown in FIG. 14A having a flat top surface702. With reference to FIG. 32, a thick coat of release layer 708 isapplied to flat top surface 702 and a depression 778 (e.g., rounded orchamfered) having the desired profile is formed in release layer 708using grayscale lithography. Specifically, depression 778 is formedusing a diffused radiation exposure to selectively and partially etchrelease layer 708. For example, using a positive etching process, theintensity of the radiation exposure is directly proportional to thedepth of the etch. Full exposure may be used to etch the deepest portionof depression 778. The rounded or chamfered portion of depression 778 isformed by decreasing the amount of radiation exposure. It will beappreciated that this process is reversed if a negative etching processis used. Further, a protrusion 780 may also be formed in depression 778by selectively altering the radiation exposure.

Where a removable end portion is desired, the depression (either in thesubstrate material 700 or release layer 708) is filled with bodymaterial 740 as shown in FIG. 33 to form the removable tapered endportion. With reference to FIG. 34, a layer of sacrificial constrainingmaterial 720 is then applied to top surface 702 having release layer 708coated thereon. This layer of sacrificial constraining material 720includes at least one (and preferably a few) cavities 782 that connectto the tapered end portion formed from body material 740. For example,FIG. 34 shows four small cavities 782. Cavities 782 are then filled withbody material 740 to establish a connection between the body of theZ-directed component and the removable tapered end portion. Cavities 782are sized so that the connection is sufficiently strong to hold thetapered end portion in place during insertion of the component into themounting hole in the PCB but weak enough that the tapered end portioncan be selectively fractured after insertion. The geometry of cavities782 may be chosen to provide a desired between insertion strength andease of removal. For example, cavities 782 illustrated in FIG. 34 have acircular cross-section. Alternatively, rectangular cavities may provideconnectors that are strong along their length but possess low strengthto shear forces along their width.

After cavities 782 are filled, as shown in FIG. 35, a layer ofsacrificial material 720 is added having cavity 722 sized to form thefirst layer of the Z-directed component as discussed above. This layerof sacrificial material 720 may also include cavities 730 extendingradially from cavity 722 as discussed above. Cavity 722 is thenselectively filled with conductive material 714, body material 740and/or any other desired materials as discussed above. For example, FIG.36 shows cavity 722 filled with body material 740. The connectors formedfrom body material 740 in cavities 782, which are positioned at thebottom of cavity 722 as shown in FIG. 35, establish a connection betweenthe tapered end portion and the first layer of the component body. TheZ-directed component is then formed layer by layer as discussed aboveusing additional layers of sacrificial constraining material 720 todefine the outer structure of the component.

FIG. 37 shows the resulting Z-directed component 820. Component 820includes a main body portion 822 having a pair of side channels 824 (oneof which is not shown). Component 820 also includes a rounded endportion 826 formed from depression 704. End portion 826 includes anarrow indentation 828 formed from protrusion 776. End portion 826 isconnected to body portion 822 by four connectors 830 formed fromcavities 782. In this manner, main body portion 822, rounded end portion826 and connectors 830 are formed integrally with each other. Theremaining area between end portion 826 and body portion 822 is open. Thegap 832 between end portion 826 and body portion 822 is preferably verysmall but is shown enlarged in FIG. 37 for illustration purposes. Aftercomponent 820 is inserted into the mounting hole in the PCB, end portion826 may be removed using a tool shaped to engage indentation 828 andconfigured to twist end portion 826 to break connectors 830 and separateend portion 826 from body portion 822.

The foregoing description of several embodiments has been presented forpurposes of illustration. It is not intended to be exhaustive or tolimit the application to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteaching. It is understood that the invention may be practiced in waysother than as specifically set forth herein without departing from thescope of the invention. It is intended that the scope of the applicationbe defined by the claims appended hereto.

1. A method for forming a Z-directed component for insertion into amounting hole in a printed circuit board, comprising: filling a firstcavity having a tapered surface with a body material to form a taperedend portion of the Z-directed component; providing a first layer of aconstraining material on top of the first cavity, the first layer of theconstraining material having a second cavity having a width that issmaller than a width of the first cavity; filling the second cavity withthe body material; providing successive layers of the constrainingmaterial on top of the first layer of the constraining material, each ofthe successive layers of the constraining material having a cavitydefining the outer shape of a corresponding layer of a main body portionof the Z-directed component; selectively filling the cavities of thesuccessive layers of the constraining material with at least the bodymaterial to form the layers of the main body portion of the Z-directedcomponent; dissipating the constraining material to release theZ-directed component from the constraining material; and firing theZ-directed component.
 2. The method of claim 1, wherein the first cavityincludes a protrusion on a bottom surface thereof that forms acorresponding indentation in an end surface of the tapered end portionof the Z-directed component for engaging a tool for removing the taperedend portion after the Z-directed component is inserted into the mountinghole in the printed circuit board.
 3. The method of claim 1, wherein thefirst cavity is formed in a substrate that supports the layers of theconstraining material.
 4. The method of claim 1, wherein the firstcavity is formed in a release layer coated on a substrate that supportsthe layers of the constraining material.
 5. The method of claim 4,wherein the first cavity is formed in the release layer by gray scalelithography.